A Ral Signalling Complex in Vesicle Traffic

在我们的细胞内部是一个复杂的交通系统。这些载体是囊泡，形状和大小各不相同，并前往细胞内的特定目的地运送货物，如：信号终止的表面生长因子受体，用于细胞壁生长或发育的蛋白质和脂质（如神经突的生长）和用于分泌的蛋白质和激素（如神经递质释放）。超过100种人类遗传疾病与该系统的一个组成部分的缺陷有关。被称为小gtpase的蛋白质为这种交通提供秩序，并允许特定的货物到达特定的目的地。它们像开关一样调节细胞功能，开启和关闭细胞内的生化过程。Ral是一种小的gtp酶，存在于大脑中，广泛分布于其他细胞中。我们发现Ral是一个大型信号复合体的一部分。当激活Ral刺激效应物时，要么是囊泡，要么是RalBP1。反过来，轻度氧化应激控制一种叫做ERp57的Ral抑制剂蛋白。本研究旨在确定Ral信号复合物在细胞中的功能作用。我们将确定Ral与哪些囊泡运输事件有关，它在该途径中使用哪种效应物，以及该效应物如何指导运输。我们还将绘制可能通过ERp57在细胞中导致Ral失活的步骤，并提出这是由轻度氧化应激介导的。分子生物学、生物化学、分子生物学、蛋白质组学和显微镜技术将用于建立这些功能。这项研究将增加对这种蛋白质对细胞，特别是神经元细胞功能的重要性的认识。这构成了理解正常细胞功能和识别引起囊泡运输疾病的进一步因素的基础。随着时间的推移，这些研究有助于开发针对此类疾病患者的特定治疗方法。

Inside our cells is a complex traffic system. The vehicles are vesicles that come in different shapes and sizes and travel to specific destinations in the cell to deliver cargo such as: surface growth factor receptors that are to have their signalling terminated, proteins and lipids destined for the cell wall for growth or development (like neurite outgrowth) and proteins and hormones destined for secretion (like neurotransmitter release). More than 100 human genetic disorders map to defects in one of the components of this system. Proteins called small GTPases provide order for this traffic and allow specific cargo to reach specific destinations. They regulate cell functions by acting as switches, turning biochemical processes on and off inside the cell. Ral is a small GTPase enzyme found in brain and broadly distributed in other cells. We have discovered that Ral is part of a large signalling complex. When activated Ral stimulates effectors, either the exocyst or RalBP1. In turn, mild oxidative stress controls a Ral inhibitor protein called ERp57. The research proposed aims to establish the functional role for the Ral signalling complex in cells. We will determine with which vesicle trafficking events Ral is associated, which effector it utilises in that pathway, and how that effector directs the traffic. We will also map the steps that may lead to inactivation of Ral via ERp57 in cells, and propose that this is mediated by mild oxidative stress. Techniques of molecular biology, biochemistry, molecular biology, proteomics and microscopy will be used to establish these functions. The research will lead to increased knowledge of the significance of this protein to cellular and particularly neuronal cell function. This forms the basis for understanding normal cell function and for identification of further factors causing diseases of vesicle transport. In time, such research aids in the development of specific therapies for sufferers of such diseases.